This application claims the benefit of Belgian Application No. 2002/0210 filed Mar. 22, 2002.
This invention relates to a face-to-face weaving machine provided to form a shed between warp yarns during successive weft insertion cycles and each time to insert one or more weft yarns into this shed, so that two backing fabrics may be woven simultaneously above one another, this weaving machine comprising upper and lower spacers, which are provided in order to extend between the said backing fabrics in the warp direction during weaving and this weaving machine comprising a weft insertion device provided in order to insert weft yarns between the upper and lower spacers.
More particularly, the present invention relates to a face-to-face weaving machine, which has been designed for weaving simultaneously two fabrics with pile loops. More particularly, it deals with a face-to-face weaving machine equipped with a four-position jacquard machine.
The present invention likewise relates to a method for weaving fabrics with pile loops, in which each time at least three weft yarns are inserted above one another at a respective insertion level during successive weft insertion cycles on a face-to-face weaving machine, an upper and a lower backing fabric being woven from respective backing warp yarns and backing weft yarns, first and second loop weft yarns being inserted between the two backing fabrics and being kept at a distance from the two backing fabrics, first pile warp yarns being alternately interlaced in the upper backing fabric and forming a pile loop over at least one first loop weft yarn, second pile warp yarns alternately being interlaced in the lower backing fabric forming a pile loop over at least one second loop weft yarn and the first and second loop weft yarns being subsequently removed, so that two fabrics with pile loops are being woven at the same time.
More particularly, the present invention relates to a method for weaving carpets having one or more zones with pile loops at the face being used as well as one or more zones with a cut pile and/or one or more zones having a ribbed structure (false bouclxc3xa9 fabric) and/or one or more zones with a pile-free effect (where the backing weave is visible) and/or one or more zones with pile warp yarns floating on the pile face (flat weave), the zones with different effects together forming a pre-determined figure or pattern.
More particularly the present invention relates to a method carried out by means of a face-to-face weaving machine according to the present invention described in this patent application.
Of course, the present invention also relates to the fabrics and more particularly to the multicoloured carpets manufactured according to a similar method.
In the European patent application with publication number EP 0 974 690 a face-to-face weaving machine is described having the characteristics indicated in the first section of this description. This machine has upper and lower lancets in order to keep the loop weft yarns at a distance from the backing fabrics. During each weft insertion, a weft yarn is inserted between the two lancets.
With this type of machines, however, the weft insertion is carried out by a set of rapiers moving between the lancets. Then the vertical distance between the upper and the lower lancets should be sufficiently long to allow the rapiers to pass freely. The distance between the lancets and the respective backing fabrics determines the loop height. With these weaving machines, the loop height should be kept limited, so that sufficient space should be available for the rapiers to move. It is a purpose of this invention to remedy this drawback.
This purpose will be attained by providing a face-to-face weaving machine designed to form a shed between the warp yarns during the successive weft insertion cycles and each time to insert one or more weft yarns into this shed, so that two backing fabrics may be woven simultaneously one above the other, this weaving machine comprising upper and lower spacers, designed to extend between the said backing fabrics in the warp direction during weaving, this machine comprising a weft insertion device designed to insert weft yarns between the upper and lower spacers, and the weaving machine according to the present invention comprising spacers carried out in such a manner that they have a first part to form loops and a second part linking up with it, and shaped such that the vertical intermediate distance between the first parts of the upper and the lower spacers is shorter than the vertical intermediate distance between the second parts of the upper and lower spacers, and further also comprising a weft insertion device designed to insert weft yarns between the said second parts of this rigid elements.
Preferably, the longer vertical intermediate distance between the said second parts is obtained because the spacers are carried out with a bend. Then the first parts (preferably the end parts) are situated between the rulers of the weaving machine, while the said second parts are situated where the shed is formed and where the weft yarns are inserted.
In such an embodiment, sufficient space is available between the second parts of the spacers to allow a weft insertion means, such as for instance a rapier, to pass freely. The loop height is determined by the first parts of the spacers. Even when the vertical distance between these first parts is rather short, the vertical distance between the second parts may be sufficient to allow the weft insertion means to pass freely. Because of this, greater loop heights may be realized.
As clearly appears from the preceding pages, such a face-to-face weaving machine is particularly suitable for weaving fabrics with pile loops according to the present invention. Because of this, fabrics with pile loops can be produced at a high productivity and at a great weaving speed. Moreover, it is possible, within a same method and on the same weaving machine, to obtain fabrics with a large number of different effects, allowing fabrics to be produced, the pile face of which will show a wide variety.
Preferably, the spacers are designed to keep the weft yarns, inserted between them, at a distance from the respective backing fabrics, while the said first parts for forming loops comprise at least two parts of a different height, so that the said distance may be modified. By shifting the spacers (in the warp direction) another part of the spacers may be used and in doing so, the height of the pile loops may be modified.
In order to support the upper spacers the weaving machine may be equipped with a stationary weaving frame.
If the weft insertion device of this weaving machine is designed to insert at least three weft yarns at the different insertion levels during successive weft insertion cycles, during each cycle, a loop weft yarn and a backing weft yarn for each backing fabric are inserted. In this manner, fabrics with pile loops may be manufactured in a very productive manner.
In a particular embodiment, at least one upper and/or at least one lower spacer comprises a cutting device in order to cut through weft yarns inserted between the upper and lower spacers.
In a very preferred embodiment, this face-to-face weaving machine is designed to weave two fabrics with pile loops and a cut pile simultaneously. Preferably, this occurs according to a method according to the present invention, as described hereafter in the patent application.
In a most preferred embodiment, this weaving machine is provided with a four-position jacquard machine, preferably an open-shed-four-position jacquard machine.
In the European patent publication EP 0 974 690 a method is also described, according to which two loop pile fabrics are woven simultaneously on a face-to-face weaving machine where each time three weft yarns are inserted above one another per weft insertion cycle. Two backing fabrics are woven above one another from warp yarns and weft yarns, while loop weft yarns, by means of upper and lower lancets, are kept at a distance from these backing fabrics. Pile warp yarns are interlaced in alternately in a backing fabric and bent over a loop weft yarn. Afterwards, the loop weft yarns are removed, so that two fabrics with loop forming pile warp yarns are formed. This method has the characteristics, which were mentioned, in the third section of this description.
The fabrics realized according to this method have a pile exclusively consisting of pile loops. In other words, the structure of the pile shows no variation at all.
It is likewise a purpose of the present invention to provide for such a method, by means of which the said drawback can be remedied and by means of which therefore two pile loop fabrics can be woven simultaneously at a high productivity having a pile structure showing a greater variety than the pile loop fabrics known.
According to the present invention, this purpose is attained by providing for a method for weaving fabrics with pile loops, where on a face-to-face weaving machine, during successive weft insertion cycles, each time at least three weft yarns are inserted at a respective insertion level above one another, an upper and a lower backing fabric being woven from respective backing warp yarns and backing weft yarns, first and second loop weft yarns being inserted between the backing fabrics and being kept at a distance from the two backing fabrics, first pile warp yarns being interlaced in in the upper backing fabric and forming a pile loop over at least one first loop weft yarn alternately, second pile warp yarns being interlaced in in the lower backing fabric and forming a pile loop over at least one second loop weft yarn alternately, the first and second loop weft yarns being subsequently removed, so that two fabrics with pile loops are woven simultaneously, and where, according to the present invention, a number of pile warp yarns are interlaced in in the upper and the lower backing fabric alternately and afterwards being cut between the two backing fabrics, so that on both fabrics also at least one zone with a cut pile is obtained.
Because of the combination of two different structures in the pilexe2x80x94pile loops and a cut pilexe2x80x94fabrics are obtained with an aspect which shows much more variety than the fabrics woven according to the methods known. Because, weaving is carried out according to a face-to-face weaving method, a high productivity is attained. For instance, with a threefold weft insertion, a weft yarn is inserted between the spacers, each time at the middlemost insertion level, while a backing weft yarn is inserted at the upper and lower insertion level for the upper and the lower fabric respectively.
An additional advantage of this method is that it allows for pile loops as well as for a cut pile to be formed in a fabric with the same weaving machine without any shifting or modification of the adjustments.
Preferably, one or several zones with a cut pile and one or several zones with pile loops being determined thus that a certain figure or pattern in the fabric is obtained. Therefore, also texts and logograms can be obtained in the fabric, for example, and this both on the face to be used and on the back of the fabric.
When applying this method, preferably use is made of a four-position-jacquard machine and more particularly of such a machine enabling to function according to the open-shed principle. If a threefold weft insertion (with three weft insertion means functioning above one another) is applied, it should be possible to insert the pile warp yarns in the following four positions:
above the upper insertion means,
between the upper and the middlemost insertion means,
between the middlemost and the lower insertion means, and
below the lower insertion means.
When carrying out this method, both a cut pile and pile loops can be formed by means of a number of pile warp yarns (this is shown in FIG. 6 for pile warp yarns (24) and (26).
With the method according to the present invention, it is likewise possible in a number of warp yarn systems to make a first and a second pile warp yarn together form a cut pile over the same weft yarns in order to create pile points with a double pile, while for at least one zone of the fabrics the proportion between the number of pile points with a double pile and the number of pile points with one single pile is determined as a function of the pile density desired.
When pile warp yarns of a particular colour are used to form pile loops and to form a cut pile, it is necessary to provide two pile warp yarns of that particular colour if the possibility of forming pile loops of that colour in the upper and in the lower backing fabric simultaneously is required. For instance, these two pile warp yarns of the same colour running together may be used in a number of warp yarn systems in order to form a cut pile over the same weft yarns. Thus, pile points with a double pile are obtained in a zone with a cut pile. Now, by not always carrying through these double pile points in a cut pile zone, but only for a fraction of the pile points, it is possible to realize a pile density that will be between 100% (all pile point single pile) and 200% (all pile points double pile). All intermediate values (between 100% and 200%) of pile density are possible by choosing a suitable proportion between the number of pile points with a double pile and the number of pile points with one single pile.
According to a preferred embodiment, according to the present invention, the upper and lower spacers are carried out as rigid elements and extending in the warp direction, are provided between the said backing fabrics, and the said first and second loop weft yarns are inserted between upper and lower spacers, because of which they are kept at a distance from the upper and lower backing fabric respectively.
Preferably, these spacers are carried out as flat lancets of a limited thickness, the flanks of which extend between the upper and the lower fabric, almost vertically next to one another, and in their longitudinal direction according to the warp direction. The distance between the lower edge of the upper lancets and the upper backing fabric determining the height of the pile loops being formed on the upper fabric. The distance between the upper edge of the lower lancets and the lower backing fabric determining the height of the pile loops being formed on the lower backing fabric.
Preferably, the said spacers are carried out in such a manner that they have a first part for forming loops and a second part linking up with it, that the vertical intermediate distance between the first parts of the upper and the lower spacers is shorter than the vertical intermediate distance between the second parts of the upper and the lower spacers, while the said weft insertion device is designed to insert weft yarns between the said second parts of these rigid elements.
In the method according to the present invention preferably, each time a backing weft yarn for the upper backing fabric, a backing weft yarn for the lower backing fabric and a first and a second loop weft yarn alternately will be inserted during successive weft insertion cycles.
Further, according to this method, a number of warp thread systems with a first and/or a second loop forming pile warp yarn, also a third pile warp yarn may be provided, which is interlaced in the upper and the lower backing fabric alternately and thereafter will be cut through between the two backing fabrics, so that at least in one fabric a zone with both a cut pile and pile loops is obtained. Because of this, an additional variety of aspect of the fabric can be created during the same weaving process.
When carrying out the method according to the present invention, in at least one fabric, with respect to weft yarns inserted during successive weft insertion cycles, also a third pile warp yarn can be interlaced over a backing weft yarn alternately in order to form cut pile legs, and a first or a second pile warp yarn can form a pile loop over a loop weft yarn, so that in at least one fabric, a zone is obtained with a pile loop and a two cut pile legs alternately. This is yet another possibility (called xe2x80x9ccut-loopxe2x80x9d weaving) which may be used during the same method in order to bring variety to the aspect of the fabric.
Yet another effect which may be applied when carrying out this method, is the pile-free effect. For that purpose, in at least one zone of at least one fabric all pile warp yarns are woven in, so that the backing fabric is visible from the pile face of the fabric.
Yet another effect is obtained when in at least one of the fabrics a number of pile warp yarns is interlaced alternately in the backing fabric and bent on the pile face over at least one backing weft yarn, so that at least also one zone with a ribbed structure, more particularly with false bouclxc3xa9, is obtained.
Further, in at least one of the fabrics, also a number of pile warp yarns may be interlaced alternately in the backing fabric and made to run floatingly on the pile face over several backing weft yarns (floating), so that also at least one zone with a flat fabric surface (xe2x80x9cflat weavexe2x80x9d) is obtained.
Preferably, tension warp yarns are provided in the backing fabrics, and dead pile warp yarns are interlaced in one the two backing fabrics either running along with the tension warp yarns or floatingly on the pile face, over one or more backing weft yarns.
In a number of warp yarn systems, also two pile warp yarns may be interlaced in opposite phase in the upper and the lower backing fabric alternately and thereafter be cut through between the two backing fabrics, so that at least one zone with a cut pile is obtained. By applying this so-called xe2x80x9cpile weaving in opposite phasexe2x80x9d, a fabric is obtained with at least one zone where the cut pile has a great pile density.
If tension warp yarns are provided in the backing fabrics, the pile warp yarns can be interlaced over at least one backing weft yarn inserted on the back with respect to the tension warp yarns (so called: woven through the back). In that manner a good pile retention is obtained.
The pile warp yarns can also be interlaced over at least one backing weft yarn, which is inserted, on the pile face with respect to these tension warp yarns. Because of this, the pile yarn consumption can be reduced.
According to a particular method according to the present invention, pile warp yarns are used which will shrink after they have been cut through. Therefore it is possible to obtain a pile height for the cut pile which is smaller than half the distance between the two backing fabrics, so that, for instance, for the cut pile and the pile loops the same pile height can be obtained.
It is obvious that the present invention also relates to fabrics with pile loops, which are manufactured by means of a method according to the present invention and therefore will comprise also at least one zone with a cut pile.
In the following detailed description, a number of weaves according to the present invention and a part of a face-to-face weaving machine are described in a more detailed manner. Its only purpose is to further clarify the principles and the said characteristics and advantages of the invention by means of a number of concrete examples. It may be clear that nothing in this description may be interpreted as a restriction of the scope of the patent rights claimed for in the claims, nor as a restriction of the field of application of the present invention.
In the following description reference is made by means of reference numbers to the attached drawings, of which: the FIGS. 1 to 11 each time represent a schematic cross-section in the warp direction of two fabrics during their being produced according to the present invention on a face-to-face weaving machine equipped with upper and lower lancets, the warp yarns of one warp yarn system, the weft yarns and one upper and one lower lancet being represented in each cross-section, and where,